Olsson claimed the 2004 Olympic gold in Athens with 17.83m

The Swede, who tore his left hamstring during the Golden League meeting in Rome on 13 July, aggravated the injury while training in Japan on Monday.

The 27-year-old, who missed the 2005 championships in Helsinki with a foot injury, said: "I just felt something go in the back of the thigh."

Olsson's decision has raised the hopes of his British rival Phillips Idowu.

Idowu had a successful start to the season, winning the Oslo Golden League title with a jump of 17.35m.

However, the Commonwealth champion later aggravated a back injury at the Norwich Union World Championship Trials, although the Londoner was determined to compete in Japan.

"I'm actually training a lot better than I was at home and the heat is actually good for my back," said Idowu.

"I've been getting treatment and physio every day from the doctors here and it seems to be working - I'm in one piece."

Olsson had also been in brilliant form earlier in the summer, emphatically winning in Paris and Rome.

SPORTS EDITORS' BLOG The World Championships is always a great sporting spectacle and Osaka promises to be no different Dave Gordon, Head of Major Events, BBC Sport

But he picked up his hamstring problem in the latter competition and his non-appearance at the DN Galan Grand Prix on 7 August, and last week's Swedish Championships was a clear indication of how serious the injury was.

The 2003 World Champion has confirmed he will sit out the rest of the season to focus on his rehabilitation.

He said: "Of course, [the leg] feels very heavy right now but I've been through many injuries before and know how I will come back."

The championships begin in Osaka on Saturday and run until 2 September.